Mice that can't grow enough tiny blood vessels in their muscles become insulin resistant, even though their muscle cells work normally when tested in a dish.
Claim Context
Reduced skeletal muscle capillary density due to muscle-specific VEGF knockout in mice leads to whole-body and muscle insulin resistance in vivo despite normal myocyte glucose uptake in vitro, demonstrating that structural microvascular rarefaction alone can impair insulin-mediated glucose disposal.
“Muscle‐specific vascular endothelial growth factor (VEGF) knockout animals have reduced capillary density in skeletal muscle and display whole body and muscle insulin resistance in vivo... in vitro (muscle incubation) assessment of insulin‐mediated glucose uptake revealed no difference compared...”
Evidence from Studies
No evidence studies found yet.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Whether increasing capillarization improves insulin sensitivity in humans.
Double-blind RCT of 100 sedentary adults with low muscle capillarity randomized to 16 weeks of aerobic training vs stretching, measuring pre- and post-intervention capillary density (muscle biopsy), microvascular perfusion (CEU), and insulin sensitivity (clamp).
Whether low baseline capillarity predicts insulin resistance development.
Prospective cohort of 400 adults with muscle biopsies at baseline to assess capillary density, followed for 5 years to assess incident insulin resistance using OGTT and HOMA-IR.
Association between muscle capillary density and insulin sensitivity.
Cross-sectional study of 60 adults undergoing muscle biopsy for capillary-to-fiber ratio, hyperinsulinemic-euglycemic clamp, and CEU to assess microvascular perfusion.